1. Field of the Invention
The invention relates generally to seismic shear wave generation apparatus and, more particularly, but not by way of limitation, it relates to specific apparatus and combinations of apparatus for inducing elliptically polarized shear waves in an earth medium.
2. Description of the Prior Art
Applicants know of no prior art that would be directly in point as regards the present invention. There has been prior discussion relative to the use of polarized shear waves, but there has not been a recognition of elliptically polarized shear waves and their possible employ in various seismic sounding schemes to increase intelligence recovery and enhance interpretability of data. It has been known that seismic shear waves in all probability do carry more information in their signal form than compressional waves due to the fact that there are at least two primary planes of polarization, i.e. horizontal and vertical shear waves, but heretofore no attention has been directed to angular relationships of seismic shear energy and the possibility of orderly elliptically polarized shear waves that may carry still additional amounts of information about the properties of refracting, reflecting and other affecting earth materials.